Electric switch



Sept l l936 G. o. w |1 M s ET Al. Re. 20,094

ELECTRIC SWITCH I Y original Filed Feb. 1o, 1934 4 sheets-sheet 1 IL?"um j G. O. WILMS ET AL ELECTRIC SWITCH Original Filed Feb. 10,'1934 44Sheets-Sheet 2 mim m Seprt. l, 1936. A G. o. wlLMs E-r AL Re. 20,094

ELECTRIC swrTcH Original Filed Feb. 10, 41934 4 Sheets-Sheet 3.THEN/5192717 Sept 1, 1936- G. o. wxLMs ET AL Re.v?20,094

ELEGTRIQ swITcH Original Filed Feb. 10, 1934 44 Sheets-Sheet 4 ReumaSept. 1', 1936 y 34 Claims.

tric switches and refers more particularly to electromagneticallyactuated control switches.

, Switches of this character may be divided into two classifications,those known as clapper type switches in which the movable contactorsswing in an arc, and those known as solenoid type switches, inwhich themovable contactors move in a straight line toward and from thestationary contacts. This invention deals with the second 1 type.

Heretofore, switches of this type were so constructed as to necessitatea large number o! moving parts connected through linkage, cams,

improperly fitting bearings. This past 'design also required accurateand difficult lining up oi coacting elements and units as the variousparts of the switch were generally separately mounted 20 upon. aninsulating base or panel.

Another disadvantage of past constructions was their inherent inabilityto meet the growing demand for reduction in size without entalling arestriction in the wiring space within the cabinet. 25 With these andother objections to past and existing switches oi thecharacter'described in mind, it is an object oi this invention toprovide ceptlonal compactness, which is so designed and o constructedthat Yno mechanical linkage of any type is employed and no lining up oicooperating units is necessary during the final assembly.

'This general object of the invention is obtained 3 tromagnet to mountand support all of its assoelated mechanism. This integral part of theelectromagnet is oi the same general conilgura- Y vtion as the magnetper se so as to save space and o afford the greatest strength. It servesasthe supporting base or frame for the entire struc--l ture andis soshaped and constructed as to, provide space and mounting means at itstopfor the switch contacts, valves or other devices, which 5 themagnetis designed to operate, and space at its sides for switches orrelays such as overload protection relays, and thus ties the entirestructure together into a compact unit.

50 an electromagnet so `designed as to afford lthe optimum of magneticemciency and of such meh chanical construction as to facilitatemachining of the parts to ailord a good surface to surface contactbetweenthe faces of the amature and 55 the magnet. e

and other mechanical expedients, all of which were subject to a host oftroubles brought on by -e an electromagneticallyoperable switch of .ex--

through the use of an integral part of the elec-v` Another' object ofthis invention is to provide lthe practical application ot theprinciples there- Re. 20,094A

ELECTRIC swrrcn y Gustav 0. Wilms and Albert J. Dawe, Milwaukee, Wis.,assignors to Allen-Bradley Company, Milwaukee, Wis.. a corporation otWisconsin Original No.1,981,534, dated'November 20, 1934.

Serial No. 710,656, February 10, 1934. Application for reissue February28, 1936, Serial'No.

UNITED sTATEs PATENT o-FFlcE (Cl. o-111) This invention relates toimprovements in elec.-

Another object of this invention is to vprovide an electromagnetconstruction in which common means are provided to hold the solenoidcoll assembled with the laminated ileld piece and to guide the armaturefor its movement through the coil, 5

Another important object of this invention resides in the provision Aoia switch'having an even number of stationary contacts and an even numberof movable-contacts, with the movable contacts mounted in pairs andbalanced against m each other, and in which the movable contacts moveina straight line during closing and opening of the switch.

`A further object of this invention is to provide a switch of Athecharacter described wherein the 15 movable contactor unit carrieddirectly by af vertically movable plungertype armature and wherein thearmature and the contactor unit form the only moving elements and movein a straight line. l. 20

Another object of this invention is to provide a novel mannerof mountingthe stationary contacts wherein a single integral member o! insulatingmaterial provides a mounting for all of the stationary contacts, adodsarcA suppressing chambers which have an arc quenching eilect asdisclosed in Patent No. 1,804,729, issued to Gustav 0. Wilms andFrederick .F.'I..oock,and providesa terminal board for the switch.

" .AnotherY object of this invention is to provide 3 ure.

With the above and other objects inv-iew which 4 -will appear as thedescription proceeds, our invention resides in the novel construction,combination and arrangement of parts substantially as hereinafterdescribed and 1 more particularly detlned by the appended claims, itbeing understood that such changesin the precise embodiment of.theherein disclosed invention may be made as come within the 'scope oithe claims.'

In the accompanying drawings, we have illustrated one complete exampleo! the physical embodiments of our-invention constructed according tothe best mode as we have so far devised for of, and in which: y I6Figure 1 is a perspective view of the complete switch;

Figure 2 is a front elevation of the switch with parts broken away landin section to illustrate structural details;

Figure 3 is a vertical section through the switch taken on the plane ofthe line 3-3 of Figure 2;

Figure 4 is a bottom view of the switch showing the manner of resettingthe overload relays Figure 5 isan enlarged detail view of one of thethermal overload relays shown separated from the rest of the switch; v

Figure 6 is a section view through the relay taken on the plane of theline 6 6 of Figure 5;,

Figure '7 is a horizontal section View looking up into the switch on theplane of the line 'I-lof Figure 2, but with the overload relaysdetached;

Figure 8 is a detail perspective view of the movable contactor and anadjacent portion of the carrier to show the manner of attaching thecontactor;

, Figure 9 is a perspective view of the lower portion of the stationarycontact mounting member;

Figure 10 is a perspective view of the laminated field piece showingthemounting bracket and the other elements which are rigidly attachedthereto,

' and the securing screw which serves to hold the armature and itsguideways assembled `with the laminated 'eld piece;

Figure 11 i-s a perspective view of a portion of the contactor carrierto illustrate particularly the manner of its attachment to the armature;

Figure l2 is a perspective view of the armature;

Figure 13 is a perspective view of the two opposed guideways removablysecured in the laminated field piece to guide the armature in itsvertical movement;

Figure 14 is a perspective view, of the magnet coil; and

Figure 15 is an enlarged detail viewto show the construction of themeeting portions of the laminated field piece and armature.

Referring now more particularly to the accompanying drawings in whichlike numerals indicate like parts throughout the several views, it willbe seen that the switch of this invention comprises essentially astationary contact assembly indicated generally by the numeral 5, and anelectromagnet assembly 6, which includes acore armature l and a movableycontacter unit 8.

In a manner to be more fully described hereinafter, both theelectromagnet assembly 6 and the stationary contact assembly 5 aremounted on a single rigid supporting bracket or frame 9 with thestationary contact assembly disposed above the magnet assembly and withthe entire structure substantially symmetrical about the vertical axisof the armature l.

The bracket -9 is in fact an integral part of the electromagnet as willbe hereinafter more fully described, and also mounts a pair of thermaloverload relays I Il on its opposite sides and a resetting deviceindicated generally by the numeral I I,

across its front forgoperative association with the relays. Fixed to theback of the mounting bracket is a back plate I2 by which the completelyassembled switch may be secured to a panel or other suitable support.This back plate I2, however, may be omitted if desired and the mountingbracket secured directly to the back of an enclosing cabinet or othersupport (not shown).

The mounting bracket or frame 9, which may be considered the skeleton ofthe switch, as all of its various elements are attached thereto, Visformed of sheet m'etal, and as best illustrated in Figure l0, has asubstantially rectangularly apertured front wall I3, a top wall I4 inthe form of a horizontal shelf or flange directed at right angles to thewall I3, and spaced side walls I5 bent rearwardly from the side edges ofthe front wall and secured by welds or other suitable means to the` topwall as at I6.

The rear edges of the side walls I5 have outwardly extending flanges Ilby which the frame is secured to the back plate I2 or directly to thesupporting surface. The side walls I5 also have forwardly and downwardlyextending arms I8 rigidly fastened thereto to mount at their outer endsthe reset mechanism II. The construction of the reset mechanism and themanner of mounting the same from' the outer ends of the arms I8 Will behereinafter described.

The front wall I3 of the supporting bracket, as

, stated, is apertured to define a rectanglar frame The laminations ofthe laminated field piece are clamped between ythe front walll I3 of themounting bracket and a substantially rectangular hollow frame member 23coextensivein size to the front wall I3, and secured thereto by rivets,or other suitable securing means 24. The mounting bracket thus forms anintegral part of the laminated field piece.

A few of the middle laminatiohs of the laminated field piece are dividedat their upper ends so as to provide aA narrow slot or opening 25through which an extended end portion 2G on the armature 'I projects. Y

The armature, as clearly illustrated in Figure 12, is built up ofsubstantially T-,shaped laminations so that the armature consists of avertical stem 2l and a horizontal head 28, rthe head being at the bottomof the armature. The outer and innermost laminations are of heavierstock and the inner lamina extends beyond the adjacent ends of the otherlaminations to provide the projected end portion 26, which as's'tated,extends through the opening 25 in-the upper closed end of the laminatedfield piece.

The inner surfaces of the armature head 28 are machinedto lie in acommon plane and provide armature pole faces 29. These'faces are adaptedto seat against pole faces the field piece I 9. The pole faces 3.0 ofthe field piece are the bottom surfaces of extensions 3| projecting downfrom the bottom of the field piece generally.

The provision of the downward extensions 3I on the bottom of thelaminated field piece, facili'- tates the machining of the laminated eldpiece 3Il-on the bottom of i precludes the formation of upset ribs onthe laces by their continuous impingement on the slotted faces 30, whichribs', il formed, might have a tendency to prevent perfect seating.

To further insure perfect seating, those portions of the laminatedileldpiece pole faces 33 which lie outside the shading coils are on a planeinwardly of the portions encircled by the coils, so that the areas oiactual contact lie'entirely 'within the shading coils and are at' theextremities of the armature head.

Attention is directed to the location o! the rivets 24, which tie thelaminations of the laminated ileld piece together. These are placed soas to provide maximum mechanical strength and a minimum of electricalloss. The two lower rivets are directly above the sealing surfaces o!the laminated field piece or areas o! impact between the laminated fieldpiece and the armature and the two upper rivets are located onoppositesides of the opening 25 through which the armature portion 26projects.

Disposed within the hollow o! the laminated field piece is a coil thatit fits easily in the hollow oi the laminated field piece and is readilypositionable therein through the open front oi the laminated fieldpiece. Terminals 35 are carried directly by thel coil to permit the sametobe connected in circuit for energization.

The coil is retained posed armature guideways 35 removably secured inthe laminated field piece. The. guideways 36 not only serve todetachably retain the coil in position, but also provide smooth guidetracks in which the armature slides, and thus positively precluderestrictive engagement between the armature and the coil. If desired,the two guideways may be formed as one integral unit, being joined atone side and separated* at the opposite side. Y

As best shown in Figure 13, the guideways 36 are channel-shaped inhorizontal cross section, havingwebs 31 and flanges 38 directed at rightVangles from the side edges of the webs. The width oi the guideways issuch that they ilt snugly between the inner faces 33 oi the ledges 22 atthe bottom of the laminated field piece.

The upper and lower portions oi the wall I3 and the front frame 23 areoffset as at lll opposite the opening 25 and the space between the lower'ends of the laminated tleld piece. These offsets are suiiicient toaccommodate the thickness ofthe webs 3l of the guldeways, the upper endsof which project into the space between the offset portions 40 oppositethe opening 25 and the adjacent outer surfaces of the laminated fieldpiece laminations. At their lower ends, the guideways have the adjacentside portions o! the laminated ileld piece laminations. In this manner,the guideways are drmly held against lateral movement in any direction.

Outwardly extending ears lower ends of the guideways provide means i'orlaminated field piece. Normally, however, disassembly of the guidewaysfrom the laminatedfield piece is prevented by ,a retaining screw 33,which passes through aligned openings in the upper closed end of thelaminated ileld piece, the'upper ends oi the guideways and an 'elongatedslot M in the projected end 23 of the armature. This single retainingscrew 43 thus serves lto readily remov- 34. This coil is of such size,

in position by a pair of op- Y laterally projecting ears Il to engage l2i'ormed on theably hold the armature, its guldeways, and the coilassembled with the laminated ileld piece.

The magnet assembly is thus readilyibuilt up and assembled with thesupporting frame' 3 and vinasmuch as the laminated ileld piece itselfmountedtherein,

through the guideways 33 guides the armature lor its movement, it is'evident that no adjustment whatever is necessary to insure accurateseating o! the armature on the laminated field piece pole laces. g

To avoid sticking of the armature in its guideways due to the magneticattraction between it and the magnet, the guideways are formed of anon-magnetic metal, preferably a non-magnetic steel alloy. For the samereason, lamina, which projects upwardly from the end o! the armature toprovide the .projected end 28, which passes through the opening 25, isalso formed of a non-magnetic steel alloy.

A steel alloy is particularly well suited to this purpose as it has therequiredA strength and being non-magnetic, it has the added advantage ofa minimum of no eddy current losses.- y

To prevent' vertical or endwise movement o! extremities of the springsare directed upwardly to engage over the outer sides o! ,the frontframes 23 and the wall I3. which is indicated generally by the numeralB, consists merely of a .cross -bar l5 of insulating material preferablymolded to shape, and directly attachable to the extended end portion 2Bof the armature, The engagement of the cross bar 45 to the armatureextended end 26` is effected by two screws 46 passed through alignedopenings in a downward projection 41 on the cross piece. The downwardprojection -is recessed as at 43 to receive the end oi the armatureprojection 25 and properly align the screws with threaded openings 49 inthe projection 26.

The assembly of the movable contactor unit to the armature thus requiresmerely the insertion o l two screws.

Projecting from the top face of the cross piece I5 and preferablysecured thereto by being imbedded directly therein, are upstandin'gposts 50 to mount the individual contactors 5I. As best illustrated inFigure 8, the manner or attaching the contactors to the posts is suchthat the contactors are readily detachable to permit renewal. For thispurpose, the posts are substantially T- shaped to provide shoulders 52at their outer ends, and their stems are reduced in'width to form narrownecks 53.

The contactors consistv ot metal cross bars 54 to the ends of whichcontacts 55 are secured. A cross shaped opening 56 is formed through themetal cross bars, the legs of whichare o! unequal length with the legso! greatest length extending longitudinally with respect tothe crossbar. These longer legs of the opening 5B are large enough to'permit thevpassage of the heads o! the T-shaped posts therethrough and the shortlegs of the openings are of a size slightly greater than the width cithe stem so that when assembled with the posts,`the shoulders 52 preventdisassembly. v

The manner o t engaging the cross bars 5l with ,the posts is quiteevident from Figure 8. As here shown. it is only necessary to turn thecross bars 5l at rightangles to their normal positions and engage thelong slots ci their cross shaped openings 5 3 over the head of the postand contacts 11 L' move the same downwardly suiiiciently far to alignthe bar with the narrow neck 53, whereupon the bar may be turned ninetydegrees to its operative position. ICompression springs 51 confinedbetween the cross bars 54 and the upper surface/of the carrier 45, serveto hold the cross bars up against the shoulders 52 and provide contactpressure.

The stationary contact assembly 5 consists4 of a block of insulatingmaterial lilll having a--ilat rear wall- 6|-, a top wall 62 disposed at'right angles thereto, and side walls 63. The undersideof the top wall isrecessed to dene a plurality of arc quenching chambers 64 separated fromeach other by partitions 65. Mounted within each chamber 64 are twostationary contacts 66.

These contacts-consist preferably of screws 61` having contact points ofsuitable fmetal secured to their heads. The contacts in each chamber areof course electrically insulated, 'and are adapted to be electricallybridged by their contactor upon engagement therewith.

The outer face of the top wall is formed with a series of ribs orpartitions 68 to provide pockets in which line terminals 69 and motorterminals 10 are mounted, the terminals being secured to the block bythe screws 61which, as stated, form part of the contacts.

A simple mounting for the contacts and terminals is thus afforded, and,as will be readily apparent, the top of the block forms a. terminalboard which, because of its accessibility, greatly facilitates theconnection of the various conductors to the switch.

The rear wall 6| of the insulated block has two vertical -counterboredopenings 1| extending therethrough, which are spaced apart exactly thesame distance as two threaded holes 12 in thetop wall or flange I4 ofthe mounting bracket 9. Screws 13 extending down through thecounterbored openings 1I in the block and threaded in the 'holes 12secure the block and consequently the entire stationary contact assemblyto the mounting bracket 9. Inasmuch as the holes 12 are accuratelylocated with respect to the laminated field piece and as the armature isguided for movement by the laminated eld piece and the movable contactorunit is carried directly by the armature, this manner of mounting theinsulating block automatically secures proper alignment between thestationary contact assemblyr and the magnet assembly.

The chambers formed on the underside of the insulated block have an arcYquenching eiect similar to that obtained iny the Patent No. 1,804,729,granted to Gustav O. Wilms and Frederick F.. Loock,

The thermal overload relays ill are conveniently attached to the sidewalls l5 of the mounting bracket 9 by screws 14 passed through theinsulating bodies 15 of the relays and threaded in holes 1G in the sidewalls l5. The holes I6k also pass through the adjacent inner ends of thesupporting arms I8.

The thermal overload relays I0 are of novel construction and comprise apair of stationary f` d to the supporting wall or body be electricallybridged by a 18. The contactor 18 is pivotthe end of an insulated arm oril" mounted on a stud 19 fixed 15 and ada; movable con ally mount lever18 r. to the body le.

Also pivot-ahy mounted on the stud 19 is a substantially il-shapedmember between the extremities oi which the lever 18' is positioned.` A

sopa-1 torsion spring BI coiled about the stud 19 with one end bearingagainst the member and its other end hooked about the lever 19'yieldably urges the lever to its contact-closing position,

A comparatively heavy coil spring 82, conned between an upturned lug 93on the member 90 and an abutment 84 formed as part of the supportingbody 15 normally yleldably tends to turn the member 80 about the axis ofthe stud 19 in a clockwise direction with respect to Figure 5. Upon suchmovement of the member 90 the lever 18' is carried vto its contactbreaking position by an ear formed as part of the .member 8D andengageable with the inner end of the lever 19.

Thermally controlled means are provided to hold the member 80 in itspotentially active position. This means consists of a spring ilnger 86rigidly secured to the member B0 and forming a pawl engageable with aratchet wheel 81. The ratchetwheel 81 is journalled on the inner end ofa tubular stem 88 mounted in the front wall 89 of the mounting body 15.Normally the ratchet wheel 81 is secured to the stem 88 by solder 90, orsome similar metal having a low fusion point, so that the engagement ofthe spring arm 86 .therewith holds the member 80 against movement byitsspring 82. the stem 88 projects beyond the front wall 89 and has aheater coil 92 encircling it. The ends of the coil are electrically andmechanically connected to terminals 93 to be conveniently connected inits proper circuit.

Upon an overload in the circuit in which the coil is connected, thetemperature rise produced therein and conducted by the stem 88 to thesolder 90 melts the same and releases `the ratchet wheel B1, thuspermitting the relay to trip, breaking the circuit across the contacts11. To facilitate connecting the contacts-18 in the proper circuit, theyare provided with terminals 94.

To reset the relays, after having been tripped, is the function of themechanism indicated generally by the numeral H. This mechanism,

as hereinbefore stated, is mounted on the outer ends of the supportingarms I9 and comprises a right angular cross piece 95 attached by screws96 to the ends of the arms I8 and slidab l y mounting'a push button 91.The stem' of the push button has a yoke 98 attached thereto. the ends ofwhich are adapted for engagement with arms 99 of insulating materialsecured to the closed outer ends oi the members 8U.

A compression spring |09 coiled about the stem of the push button andconfined between the button and the cross piece 95 yieldably. holds theyoke in its inoperative extended position spaced suiiiciently far fromthe arms 99 so as not to restrict their movement during tripping of therelay.

To reset either or both relays it is only necessary to depress the pushbutton, whichaction, taking effect through the yoke and the arms 99,moves the members 8U about their pivotal mountings to their normal setpositions. The mechanism oi' the relays is preferably enclosed by a.

cover IUI of thin insulating material. Figures 5 and 6 show the relaywith this cover removed. Mounting the overload relays and the re-setmechanism on the supporting br-acket as described, affords a verypractical and eiiicient construction and insures accurate alignment`between the relays and the re-set mechanism.

The mounting of the heater coils as shown and )described on the front ofthe relays facilitates The outer end of.

f removal and cessible from the front of replacement of the coils, asthe screws holding the coils in place are readily acthe switch.

While the particular construction of the overload relays is the separateinvention of Gustav 0.- Wllms and forms the subject matter of thecopending application, Serial No. 725,447, led May 14, 1934, it has beenshown and described herein to more adequately define the presentinvention.

From the foregoing description taken lin connection with theaccompanying drawings, itwill be readily apparent to those skilled inthe art to which this invention appertains, that this invention providesan electromagnetically operable switch of novel design and construction,and that by this novel design and construction compactness andsimplicity are assured.

It is also evidentthat the manufacture of the switch is materiallyfacilitated as all ofthe various sub-assemblies may be entirely built upin individual production units, and then brought to a final assemblydepartment where the insex-tion of but a few screws completes the entireassembly without requirement for costly lining up of the coactingelements.

`It is also evident that by reason of the complete elimination oflevers, cams and similar wearing joints and connections, the switch hasan exceptionally long life. In fact, the only real wear during use isconfined tothe readily replaceable stationary and movable contacts.

What we claim as our invention is:

l. An electromagnetically operated switch comprising an electromagnethaving a laminated field piece, an operating coil mounted within thefield piece, an armature guidedfor axial sliding movement in a fixedpath through the field piece and the operating coil, a movable contactercarried by the amature to be movable therewith, a stationary contact, amember to which the stationary contact is rigidly attached, and means ofattachment to mount the entire device to which the field piece isdirectly and permanently fixed and to which said member is directlysecurable in a predetermined position' with respect to the field pieceso that thecontact carried thereby is automatically aligned with thecontacter upon the attachment of said member to the means of attachment.

2. In an electromagnetically operated switch, a stationary contactassembly comprising, an insulating member having arc quenching pockets,contacts in said pockets and terminals for the contacts mounted directlyon the exterior of the said insulating member, an electromagnet assemblyhaving a laminated field piece, a coil disposed in the field piece, andan armature guided i'oraxial sliding movement through the field pieceand coil, a movable contactar unit carried by the armature to be movedthereby toward and from the stationary contact assembly, said movablecontactor unit having contacts movable into the pockets of thestationary contact assembly to engage the contacts therein, and a singlerigidI supporting member forming a permanent part f the field piece andto which the stationary contact assembly is directly secured to insurealignment between the contacts.

3. In an electric switch, an electromagnet assembly including alaminated field piece, an operating coil mounted within thefield pieceand an armature guided through the coil by the field piece, means ofattachment to mount the entire device rigidly secured to said ileldpieceto form cured, and means to an integral part thereof and having a holein a portion thereof accurately located with respect lto the eld pieceand the path of movement of the armature, a movable contactor unitcarried by the armature and movable therewith in a fixed path,astationary contact assembly including contacts and a member to whichsaid contacts are semount the stationary contact assembly on sald\ meansof attachment in- -cluding an element engaged with the member to whichthe stationary contacts are secured and received in the hole in saidmeans of attachment, the engagement of said element in the hole liningup the stationary contact assembly with the movable contacter unit.

4. In an electric' switch, means of .attachment to mount the entiredevice having two angularly disposed walls, a laminated field piecefastened directly and permanently to one of said walls so that said wallforms an integral part of the field piece, an operating coil mounted inthe field piece, an armature guided for axial sliding movement throughthe field piece and the coil and parallel to said wall, a movablecontacter carried by said armature to be movable therewith, a stationarycontact, and means tomount the stationary contact from the other of saidWalls in line movable contactor.

5. In an electromagnetically actuated switch, means of attachment tomount the entire device with the having angularly disposed walls, alaminated field piece assembled on one of said walls which issubstantially coextensive in size and shape to the field piecelaminations, said field piece being provided with a substantiallyvertical passage therethrough, an armature slidably disposed in saidpassage, a Vmovable contacter unit carried by the armature upper end,and a stationary contact assembly secured to the other of said angularlydisposed walls with its contacts arranged for engagement by the contactsof the movable contactor unit.

' `6. In an electromagnetically operated switch, a rectangular laminatedeld piece having a gap in themiddle of one side thereof, an armaturecore composed'of a plurality of laminations secured together, a centralone of'said laminations projecting beyond the adjacent ends of theothers to provide means for attaching a movable contactor carrier' tothe armature, said armature beingk substantially T-shaped in form,having a shank and a head, said shank being movable in said gap so thatYa variable spacing occurs between the end of said shank beyond whichsaid central lamination projects and the interior o f said field pieceand a nonvariable spacing occurs y between the sides of said shank andthe sides of said gap, and pole faces arranged one on each side side ofsaid gap, a substantially T-shaped armature having a shank and a head,said shank being. slidably disposed within said gap, said armature beingcomposed of a plurality of laminations sevgap,oppositely arranged polefaces one on each l cured together and one of its medial laminations vextending beyond the others at the end lof said shank to project throughthe narrow opening in the upper closed end 'of thefield piece, andpolesitionable between the side arms of the field piece y through theopening of one of said members, an armature movable between the sidearms of the iield piece and through ther center-of the coil, and amatureguiding track removably secured in the eld piece to guide the armaturefor movement and to detachably securethe coil assembled with the fieldpiece.

9. In an electromagnetically actuated switch, a

laminated eld piece of substantially U-shape and having an openingAthrough its closed end, a coilA disposed between the side legs of thefield piece, an armature slidable between the side legs ofthe eld piecethrough the center of the coil and having a part projecting through theopening in the closed end of the field piece, guideways removablydisposed between the side legs of the iield piece to guide the movementof the armature and retain the coil assembled withthe iield piece, andcommon means to retain the guideways and the armature assembled with thefield piece.

10. In an electromagnetically operated switch, a laminated eld piece ofsubstantially U-shape having an opening through its closed end, a coildisposed in the space between the side legs of the field piece,guideways removably positioned between the side legs of the field pieceand extending up through the hollow ofthe coil to retain the collassembled with the field piece, said guideways having portions overlyingthe sides of the closed end of the field piece, an armature slidable insaid guideways and having an extended end portion projecting through theopening in the closed end o1' the eld piece, a movable contactor carrierattached to said extended end portion of the armature, and a retainingmember passed through aligned openings in the closed end portion of thefield piece, the projected portions of the guideways and an elongatedslot in the extended end portion of the armature to retain the guidewaysand armature assembled with the field piece.

11. In an electromagnetically operated switch, a laminated eld piececomprising a plurality of substantially U-shaped laminations assembledbetween two hollow rectangular members, a coil disposed between the sidearms ofthe U-shaped field piece and adaptedA to be so positioned bypassage through one of said rectangular members, guideways removablysecured between the side legs.

of the field piece and extending through the hollow of the coil toretain the coil' assembled with the field piece, an armature guided foraxial movement by said guideways, and yieldable means confined betweenone end of the coil and an adjacent portion of the field piece to holdthe coil against an opposite portion of the field piece to retain thesame against axial movement.

12. In an electromagnetically operable switch, a laminated field pieceincluding a plurality of laminations secured between two substantiallyfiat sheet metal members, said iield piece having a passage therethroughfor the reception of an armature, an armature slidable in said passageand having a part projecting beyond one end of the eld piece, a movablecontactor assembly mounted on said part of the armature to be movtactsof the movable contactor assembly.

13. In an electromagnetically operable switch, an electromagnet assemblyincludinga supporting laminated eld piece as a' permanent part thereofand a movable armature, a stationary contact assembly comprising a blockof insulating material recessed at its underside to provide an arcquenching chamber, a contact carried by said block and located on thetop wall of saidl chamber, means to secure said block to the laminatedfield piece of the electromagnetassembly, and a movable contactorcarried by the armature and movable up into said arc quenching chamberto engage the contact therein.

14. In an electromagnetically operable switch, anl electromagnetassembly comprising a laminated field piece, an armature movable in theiield piece, and a supporting frame rigidly and permanently attached tothe eld pieceto -form an integral part thereof, a stationary contactassembly comprising a block of insulating material recessed at itsunderside to define a plurality cf material to the supporting frame ofthe electromagnet with its stationary contacts properly aligned with themovable contactors.

15. In an electric switch, a stationary contact assembly comprising aninsulating member shaped to define a plurality of separated arequenching chambers substantially closed on all sides save the bottom,stationary contacts mounted on the inner walls of said arc quenchingchambers, and terminals for said contacts mounted directly on theexterior of said insulating member.

16. In an electric switch, a stationary contact assembly comprising anintegral member of insulating material shaped to define arc quenching ichambers substantially closed on all sides save the bottom, contactswithin said chambers, terminals for said contactsmounted directly on theexterior of said member, andcommon means to secure said contacts andterminals to said member and electrically connect the same.

Y1'7. In an electric switch, a stationary contact assembly comprising anintegral block of insulating material recessed onits underside to definea plurality of separated are quenching chambers substantially closed onall sides save the bottom, a pairof electrically spaced contacts in eachof said chambers, terminals on one external face of said block ofinsulating material electrically connected to said contacts, wherebysaid external face of the blck serves as a terminal board foi theswitch, and contactors movable into said chambers t engage andelectrically bridge the contacts therein.

18. In an electromagnetically operated device', an electromagnet havinga rectangular laminated field piece with a medial gap in one of therectangular sides, pole faces adjacent said gap. a

Tshaped amature having a head and a shank, said shank being gulded'formovement through said gap in parallel relation to the sides thereof, sothat opposite inner sides of said head of said armature are movable uponenergization of the electromagnet into faces, an instrumentalitycarriedby the amature to be movable therewith in a deflnitenpath,l andyanother instrumentality carried directly'by the eld piece of theelectromagnet to be in direct alignment with the armature carriedinstrumentality and to be engageable thereby to perform a predeterminedfunction.

19. In an electromagnet device, a vfield piece comprising laminationsassembledA between two rigidly connected members, one of said membershaving means of attachment to mount the entire device on a support andhaving means to directly mount instrumentalities associatedwiththe'electro'magnet.

20. In a devicel of laminated iield piece, end

the character described, a

' the field ,piece is permanently assembled, a supporting iiange on oneof said end plates forming means of attachment to mount the entiredevice, and to afford a base for an instrumentality associated with theiield piece, whereby such instrumentality upon attachment to said basehas an accurate, definite, relative position with respect to the fieldpiece.

2i. In a device of, the character described, a laminated field pieceassembled between end members which are rigidly secured thereto, anarmature guided by the field piece for movement in a fixed path, aninstrumentality carried by the armature and movable therewith in a fixedpath. a second instrumentality cooperable with the armature-carriedinstrumentality to effect a predetermined function, and means carried byone of said end members to form means for attachment to mount the entiredevice and to mount the second instrumentality and insurel properalign-ment with the armature carried instrumentality.

' 22. In a device of the character described, a laminated field' vpieceassembled between end members which are rigidly secured thereto, anarmature guided by the field piece for movement in a fixed path, aninstrumentality carried by the armature and movable therewith in a fixedpath, a second instrumentality cooperable with the armature-carriedinstrumentality to effect a predetermined function, means carried by oneof said end members to mount the second instrumentality armature-carriedinstrumentality, and means carried by 'said designated end memberattached to a support to mount the entire device from said support. d

y23. In an electromagnetically operated device, comprising a. laminatedfield piece provided with a pole face, an armature cooperating with thefield piece and having a pole face engageable with the fieldV piecepoleface, said field piece having a slot extending inwardly from its poleface. and a shading coil in said slot, the armature pole face beinggrooved in line with the slot of the iield piece to preclude theformation of a raised rib on the armatu'repole face by continuedimpingement thereof Aon the slotted portion of the field piece poleface. v l

24. In an electric switch, a stationary contact assembly comprising aninsulating member shaped to define a plurality of separated arcquenching chambers substantially closed on all engagement with saidpoleplates between which and insure proper alignment with the.

vexterior of said insulating member, certain of said terminals havingportions thereof bent down over the front wall of said insulating memberand other terminals having portions thereof bent up-` wardly to projectsubstantially vertically from the top wall of said insulating member,and terminal screws threaded in said downwardly and upwardly directedportions of the terminals so that the heads of all of the screws facethe front of said insulating member.

25. An electromagnet comprising a hollow laminated field piece, anoperating coil provided with an opening through its center disposed inthe hollow of said field piece, and means to readily detachably securethe coil to the field piece, comprising opposed channel-shaped guidesextending through the opening of the coil with their ends readilydetachably engaged with the field piece.

26. In anelectromagnet, the combination of a laminated field piecehaving d a coil-receiving opening, an operating-coil disposed in saidopening and having an opening through its center, an

armature movablel throughv the opening in the coil, and common means forguiding the armature and securing the coil in the field piece comprisinga pair oi' guides substantially U-shaped in cross section extendingthrough the opening in v the coil with their ends engaging the iieldpiece.

` nations secured together, a central one of said laminations consistingof a non-magnetic ferrous alloy .projecting beyond the adjacent ends ofthe others to provide means for attaching a movable contactor carrier tothe armature.

29. In an electromagnetically-operated switch,

a substantially inverted U-shaped laminated field piece having a narrowopening through its upper closed end portion, an armature slidablydisposed between the side legs of the field piece, said armature beingcomposed of aplurality of laminations secured together, and one of itsmedial laminations consisting of a nonmagnetic ferrous alloy extendingbeyond the others to project through the narrow opening in the upperclosed end of the field piece whereby a movable contactor y carrier maybe attached to said projected lamination of the armature.

30. In an electromagnet, a laminated field piece composed of a pluralityof substantially U-shaped laminations assembled between two hollowrectangular members and having a narrow opening through its upper closedend portion, a coil disposed'between the side arms of the field piece,

said coil being rigidly positioned between the side arms of thefleldpiece through the opening of one of saidmembers, an armature movablebetween the side arms of the-field piece and throughA the center of thecoil, said armature being composed of a plurality of laminations securedtogether, and one of its medial laminations consisting of a nonmagneticferrous alloy and extending `beyond the others to project through thenarrow opening in the upper closed end of the field piece, and arms.;`

' piece.

31. In an electromagnetic switch, an electromagnet assembly including alaminated eld piece,a movable armature and a supporting frame rigidlyjoined to the field piece and in itself providing a rigid support forthe entire switch capable of direct attachment to a. support, asta--ltionary contact assembly including a member' of insulating material anda contact carried by said member and locatediat the underside thereof,means to secure said member to the supporting frame of the electromagnetassembly in a definite xed position with respect to the electromagnetassembly, and a movable contacter operable by the armature and guided bysaid electromagnet assembly Vfor movement up into engagement with thestationary contact.

32. In an electromagnetically actuated switch, a stationaryelectromagnet assembly includinga laminated iield piece and a supportingframe rigidly joined to the ileld piece and in itself providing a rigidsupport for the `entire switch cavpable of direct attachment to asupport, a stationary contact assembly comprising aA member.

of insulating material and a contact carried by said member and locatedat the under side thereof, means rigidly connecting said member with.

the supporting frame of the electromagnet assembly in a definite xedposition with respect to the electromagnet assembly, and a movablecontactor a'ssembly comprising an armature guided by said electromagnetassembly for movement t ward and away from thev stationary contactassembly, a movable contacter carrier solidly connected with thearmature, and a contactol-l on said carrier adapted to be moved into andout of engagement with the stationary contact by the armature.

33. In an electromagnetically actuated switch, a movable contacterassembly comprising, a core armature composed of a plurality oflaminations secured together. a central one of said lamina'- tionsprojecting beyond the adjacent ends of the others, a movable contactercarrier, and means securing the contactor carrier to the projectingportion of said central lamination, said means holding the carrieragainst rocking movement with respect to the armature.

34. In an electromagnetically actuated switch, a stationaryelectromagnet assembly including' a field piece, a movable contactorassembly cooperating with the eld piece and comprising, a core armaturehaving a shank and a head portion integral therewith, whereby the corearmature is substantially T-shaped and symmetrical about a longitudinalaxis running centrally through the shank, said head portion beinglocated to one side o1' the electromagnet and the unheaded'portlon ofthe shank extending toward. the opposite side thereof, an insulatedcontactor carrier, and means rigidly securing the carrier medially ofits length to the unheaded end of the shank with the may,jor axis of thecarrier normal to said longitudinal axis sov that the composite assemblyis symmetrical and balanced about said longitudinal axis.

GUSTAV O. WILMS. ALBERT J. DAWE;

